Microwave technology in baking

Dielectric properties of microwave-baked cake and its constituents over a frequency range of 0.915–2.450GHz

“…However, the results are in agreement with studies by Seras et al (1987) and Kent (1987), who suggested that the low dielectric properties of flour are a result of the interactions of water with the polysaccharide matrix. The magnitude of the dielectric properties of raw batter and Madeira cake are in accordance with the results of Schiffmann (1992). The author estimated that batters, because of their relatively high proportions of water, would exhibit high dielectric constants, in the range 20-50, and loss factors between 5 and 20, making them quite microwave absorptive.…”

“…The author estimated that batters, because of their relatively high proportions of water, would exhibit high dielectric constants, in the range 20-50, and loss factors between 5 and 20, making them quite microwave absorptive. Schiffmann (1992) also estimated (by extrapolating data for wheat and other agricultural products) the dielectric constant of flour to be between 2 and 4, and the loss factor to be of the order 0.2-0.8. The aforementioned dielectric property observations indicate that Madeira cake batter and its components are promising candidates for use in a microwave baking process.…”

Technology of Breadmaking

“…Three technologies that are proven experimentally but not commonly implemented commercially offer the potential for markedly reducing baking times. One is dielectric heating (Ovadia 1994), using either radio frequency or microwave power (Schiffmann 1993), where the energy is supplied through the bulk of the dough piece, and it is therefore not surprising that baking times can be halved. The volumetric transfer of energy will not give rise to an evaporation front in the same way as conventional baking, so any crust formed will be thin and delicate, nor will the skin temperatures reached be high enough to generate colour and flavour in the crust.…”

Moisture adsorption isotherms of microwave-baked Madeira cake

“…This application of microwave heating is of particular interest because of the operational efficiencies it affords. The unique heating mechanisms of microwaves permit dramatic energy savings in many instances (nearly all the microwave energy is coupled into the material to be heated and is not expended in heating the air, conveyor or other parts of the equipment), as well as benefits not obtainable from other, more conventional methods, such as, uniform heating throughout the material; better and more rapid process controlling (offers instantaneous heat generation and variation of power); reduction in floor space requirements; improved nutritional quality, and desirable chemical and physical effects promoted by the heat generated by the microwaves such as expansion, drying, protein denaturation and starch gelatinization (Schiffmann, 1992). The most prominent advantages of microwave heating are the reachable acceleration and time savings, and the possible volume, instead of surface heating (Reiger & Schubert, 2001).…”